Assoc. Prof. Dietmar Dommenget - Honours

ENSO: Climate change

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Oceanography

The El Nino Southern Oscillation (ENSO) mode is the most important mode of natural variability on time scales from seasons to a few years. State-of-the-art climate models (e.g. CMIP5 models) predict different kind of changes in the behaviour of this mode. A recent study by Cai et al. 2021 suggests that both extremes, El Nino and La Nina, become more extreme. This study is based on some newly developed non-linear representation of ENSO modes (Dommenget et al. 2013) and is somewhat in contrast to what the IPCC report suggests. This project will aim at analysing the climate change signal in ENSO using the approach of Cai et al. 2021 and Dommenget et al. 2013. The analysis will focus on describing what the changes look like and how they can be explained by dynamical changes.

El Nino dynamics in seasonal forecast simulations

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science / Oceanography
Support Offered: potentially Bureau of Meteorology
Collaborating organisation(s): potentially Bureau of Meteorology

The El Nino Southern Oscillation (ENSO) mode is the most important mode of natural climate variability. Seasonal weather forecasts are depending primarily on predicting the evolution of ENSO correctly. However, it has been shown that State-of-the-art climate models (CMIP models) do simulate ENSO with a wide variety of characteristics and significant biases towards observations. Such biases are also potentially affect seasonal forecast. In a recent study, it was shown that ENSO dynamics, and biases therein, can be very well diagnosed in the frame work of the ENSO recharge oscillator model. The focus of this project will be on applying the ENSO recharge oscillator model diagnostics to the Bureau of Meteorology new seasonal forecasting system to evaluate the ENSO dynamics, biases therein, and potential avenues of improving the forecasting system in respect to ENSO forecasts.

Changing Modes of Variability

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Stochastic Variability

Global warming will change the mean climate in many different ways. It will also affect the modes of variability. The project will analyse State-of-the-art climate models (e.g. CMIP5 models) to understand how large-scale modes of climate variability will change. This will be done within the concepts of stochastic climate variability, using different methods, such as principle component analysis, power spectral analysis and stochastic modelling.

Modes of tropical, relative SST variability

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science

Tropical variability on the larger scales, such as ENSO, are usually analysed on the basis of SST anomalies. However, atmospheric convection and related processes, such as tropical cyclones, are often not related to SST anomalies itself, but are related to SST anomalies relative to the tropical mean. This project will analyse the modes of relative tropical SST anomalies and how they relate to important atmospheric large-scale variability.

Simple Climate Model Projects

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science

We have developed the simple climate model: Globally Resolved Energy Balance (GREB) model (aka Monash Simple Climate Model), that can simulate the global climate response to external forcing. It can compute 100,000yrs of simulation per day on a standard PC computer. Thus it is a nice and simple tool that allows for wide range of studies. Projects examples could be on: Simulating ice age cycles over the last 3 mill. years, include stochastic weather variability, do geoengineering studies, build strange worlds or exo-planets or developing new elements like ocean carbon, better precipitations at higher latitudes, soil moisture, aerosols or atmospheric circulation response. Detailed projects with the GREB model will be formulated together with the student, as there are simply to many different things that could be done with this model to list them all here.

Webpages:

Simulation of Ice-Age cycles with the GREB Model

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science

We have developed the simple climate model: Globally Resolved Energy Balance (GREB) model (aka Monash Simple Climate Model), that can simulate the global climate response to external forcing. It can compute 100,000yrs of simulation per day on a standard PC computer. An important aspect of the last few million years of climate variability are the global 100kyrs ice-age cycles. The aim this project is to simulate the past million years of climate variability with the GREB model and try to gain understanding on what controls the global 100kyrs ice-age cycles. This project will be a combination of literature study, climate model development and analysis of model simulations.

Webpages:

A Carbon Cycle Model for the GREB Model

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science

We have developed the simple climate model: Globally Resolved Energy Balance (GREB) model (aka Monash Simple Climate Model), that can simulate the global climate response to external forcing. It can compute 100,000yrs of simulation per day on a standard PC computer. An important element for long term (>1000yrs) climate variations is the global carbon cycle, which exchanges CO2 between the atmosphere and other reservoirs. The aim this project is to build a simple carbon cycle model for the GREB model. This project will be a combination of literature study, climate model development and analysis of model simulations.

Webpages:

Tropical Precipitation change and its relation to the control climate

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science / Oceanography

State-of-the-art climate model project a complex pattern of future precipitation changes: this involves a weakening of the tropical circulation, shifts in the circulation and precipitation patterns, and strong uncertainties between models. Much of these projected changes look similar to the seasonal cycle and El Nino like shift in the control climates of the model simulations. The projects aims at analysing the model simulations precipitations changes, and put them into context with the control climate. The aim is to build a simple conceptual model, that describes the future precipitation change pattern as a function of the control precipitation pattern of the seasonal cycle and El Nino.

CMIP model errors in climate sensitivity

Supervisor(s): Dietmar Dommenget
Field of study: Climate Dynamics / Atmospheric Science / Oceanography

The future climate change projections, such as published in the IPCC report, are based on state of the art coupled general circulation models. These simulations are made available for researchers in the Coupled Model Intercomparision Project (CMIP). The CMIP model simulations have large uncertainties in the projections of future climate change (the climate sensitivity) and also have large uncertainties in the simulation of the current mean climate. The project should focus on analysing the relationships between the biases in the mean climate and the differences in the climate sensitivity. The project could either focus on errors in the surface temperatures or on errors in the rainfall patterns

For further information, contact Dietmar Dommenget